Particularly, with the advancement of a network technology and the spread thereof since 2000, a communication means between users has progressed from an electronic-mail, a web site, and a bulletin board system to a blog that allows individuals to easily dispatch information, a social networking service (SNS) that allows many users to exchange various opinions with one another, an instant messenger that includes many additional functions and pursues real time nature, and a video hosting service in which a number of users share moving images posted by an unspecified number of users and can exchange comments and the like.
For the development of a computer network technology, considerable efforts have been put into not only an improvement in a communication speed but also an improvement in a display technique of content on a network. For example, content posted on a web site has been initially described in a hypertext markup language (HTML), and then the markup language has evolved to an extensible markup language (XML) having a more extended function. From the mid-2000s, a technique of capable of dynamically executing a web application without accompanying screen transition which is called Ajax (Asynchronous Java (a registered trademark) Script+XML) has become recognized by the world. While the develpment, hardware has dramatically improved processing capabilities in all of personal computers, work stations, and supercomputers.
Meanwhile, in the world of computer entertainment, each company has applied its proprietary specification to a content display format, but hardware has evolved from an initial stand-alone video game machine to a network compatible home-use game machine with a high-performance processing engine.
Further, with the advancement of technology, a communication means on a network is evolving such that real time nature is further required in each operation environment.
Meanwhile, in the world of computer entertainment, real time nature and high-speed responsiveness have been pursued from early video game machines, and in recent home-use game machines, real-time computing has been improved in quality along with improvement in hardware performance, and for example, it is possible to render 3D graphics in real time.
As an example of an application to implement real time nature, there is an instant messenger. The instant messenger is under the assumption that a packet message transmitted from a certain user instantly arrives at a counterpart user except for a delay time (latency) caused by a physical restriction of a device. Further, a packet message transmitted or received with respect to an instant messenger includes relatively short text data, and thus real time nature is generally achieved.
Meanwhile, an electronic conferencing system has been obtained by developing the idea of an instant messenger. For example, a voice over IP (VoIP) is used in a remote conference on the Internet or a local area network (LAN). In recent electronic conferencing systems, it is possible to share a moving image as well as a text or a sound between a plurality of participants as information transmitted or received in real time.
For example, an invention disclosed in Patent Literature 1 is to provide a video conference system with a structure for enabling a smooth conversation progress even in a remote conference to be performed by a plurality of persons through a plurality of terminal devices. The video conference system includes a management table for managing users of a plurality of the terminal devices in a state that the users are classified into an interlocutor mode in which the progress of a specific agenda is centrally performed and a observer mode other than the interlocutors, and a communication control means for delivering information necessary for an interactive conversion to the terminal device of each user classified into the interlocutor mode, separately editing information by a medium selected among information associated with a conversation between the users classified into the interlocutor mode as delivery information, and then delivering the edited information to the terminal device of each user classified into the observer mode.
A problem that is desired to be solved by this invention is to realize a smooth conversation progress by limiting the number of receivers and callers in a limited communication band.
Further, a form in which a number of other users view a real-time interactive communication state between both parties is widely embodied even in an on-line game as a spectator mode.
In other words, the following invention has been proposed as an example of an application to realize real time nature in computer entertainment (Patent Literature 2).
An invention disclosed in Patent Literature 2 is to provide a communication game system that promotes communication between game players by providing various ways of playing, and the communication game system includes a game client system and a game server system that communicates with the game client system. The game server system includes a database that stores group information used to associate a plurality of game client systems as a competition group, and is configured to decide a competition combination from the game client systems belonging to the same competition group, manage transmission and receipt of data between the game client systems decided by the combination to execute a competition, and decide a next combination according to a result of the competition. Each game client system has a unique character selecting function and a function of chatting while viewing.
Particularly, data related to a game can be transmitted or received in real time, between game client systems whose opponents are decided among a plurality of game client systems, through the game server system, and each of the plurality of game client systems can chat with another game client system in a spectating state through the game server system while spectating a game.
This type of game sharing experience by a plurality of players mostly depends on performance of a game client system having powerful calculation resources and a memory, and it is still difficult to implement a real-time service of a game with high expressive power by a number of players only by a centric game server system and thin clients.
Further, as a communication means on a network develops, an infringement of portrait rights, a copyright infringement, uploads of harmful information or illegal content became a problem, and thus a protection technique of personal information and a removable technique of harmful content have become developed (Patent Literature 3).
An invention disclosed in Patent Literature 3 is to provide a new moving image censoring technique to solve a problem of a conventional moving image censoring technique by producing and displaying a thumbnail list by which moving image censorship including that of a copyright infringement and other criteria can be efficiently performed. Moving image data of a censorship target is divided into scenes, and various kinds of events included in input moving image data are detected. The detected events cause one or more thumbnail images to be extracted for each divided scene, and importance degrees on the extracted thumbnail images are calculated based on the detection result of the detected events. The extracted thumbnail images are rearranged in order of the calculated importance degrees and displayed in the form of a list. Thus, by displaying the thumbnail images extracted from the moving image data of the censorship target in order of the importance degrees in the form of a list, a time and effort to determine whether or not to open the images to the public can be alleviated, and the determination can be rapidly made.
In this invention, the determination is non-real time manual processing and thus is difficult to be applied to a system in which a number of moving images are uploaded in real time and re-delivered.
Further, with the recent spread of the Internet, the amount of information on a network has increased, and an information retrieval technique has advanced. For example, many portal sites having a powerful search engine are being run. Further, techniques of analyzing search keywords or access history of visitors and delivering web pages or advertisements that are to the visitor's preference have been developed, and marketing based on keywords used by visitors are being conducted.
For example, there has been proposed an information providing device capable of easily providing information useful for a user with a high degree of accuracy (Patent Literature 4). The information providing device includes an access history storage means that stores access frequency information representing the frequency with which a user has access to each content in association with user identification information identifying a corresponding user, an inter-user similarity calculating means that calculates an inter-user similarity indicating similarity of an access trend to content between users based on the access frequency information stored in the access history storage means, a content score calculating means that calculates a content score, which is information representing usefulness of content for users from the access frequency information of each user which is weighted by a similarity degree between users, an index storage means that stores the content score of each content calculated by the content score calculating means in association with the user identification information, a query input means that receives an input of a query including the user identification information which is transmitted from a communication the terminal device, a provision information generating means that acquires content identification information of content appropriate for the query received by the query input means, and generate provision information from the acquired content identification information with reference to the content score stored in the index storage means in association with the user identification information included in the query, and a provision information output means that outputs the provision information generated by the provision information generating means to the communication terminal device.
In this invention, a means of extracting each user's preference or action history, for example, using the user's interest degree using information, for example, image information other than information based on a language or a text is not provided.
Further, as studies related to image recognition by a computer, studies on various techniques for a general object recognition technique have been conducted (Non-Patent Literatures 1 to 4), and particularly, a technique called “Bag-of-Features” or “Bag-of-Keypoints” has been proposed in 2004 (Non-Patent Literature 5).